Rick and Mitt get personal in Ariz.

MESA, Ariz. — Mitt Romney and Rick Santorum tore into each other’s records on government spending, health care, abortion rights and more on Wednesday night, quickly turning the crucial Arizona primary debate into a flurry of charges and counter-charges that reflected the bitter tone of the GOP race.

The two leading Republican candidates squabbled in a petulant, personal fashion on the stage here, with Romney opening the attack on Santorum as an inveterate pork-barrel spender.

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The cross fire continued throughout the nearly two-hour debate, doing only a little to clarify the GOP primary but bloodying both candidates — and doing more damage to Santorum, who was most frequently on the defensive.

“You voted for the Bridge to Nowhere,” Romney jabbed at Santorum early on. “When I was fighting to save the Olympics, you were fighting to save the Bridge to Nowhere.”

The former Pennsylvania senator defended his record on spending, acknowledging that he made missteps in his congressional career but branding Romney as a hypocrite when it comes to federal earmarks.

“He’s out there on television ads right now, unfortunately, attacking me,” Santorum said. “He not only asked for earmarks for the Salt Lake Olympics, … he did it as governor of Massachusetts, three or four hundred million dollars.”

To voters in Michigan and Arizona — the next two presidential primary states, which vote on Feb. 28 — the accusations may already be familiar. Romney and a super PAC supporting him have poured money into television ads blasting Santorum as a Washington insider who can’t be trusted by fiscal conservatives.

Santorum has responded on the air with ads questioning Romney’s conservatism, though he has been outspent by pro-Romney forces.

It wasn’t only on fiscal issues where the Republicans lit into each other. Indeed, no subject seemed too small or too petty for the debate — including the 2004 Pennsylvania GOP Senate primary.

The Republicans demonstrated a personal animosity that no paid television ads can convey.

Seated next to each other at the debate table, Romney and Santorum not only attacked each other on their policy differences but sniped with a level of sarcasm that exceeded what viewers have seen in previous debates.

After Santorum delivered an extended critique of Romney’s record on taxes, Romney bit back: “I didn’t follow all that.”

When Romney charged at Santorum on the topic of earmarks, the Pennsylvanian all but called his opponent a liar.

The two other candidates on stage, Newt Gingrich and Ron Paul, played important supporting roles, but neither seized center stage for more than a few seconds at a time.

They did, however, serve to amplify the Romney-Santorum feud, with Paul calling Santorum a “fake” conservative and Gingrich accusing Romney of a two-faced position on earmarks, as he criticized Santorum’s spending while defending federal support for the Salt Lake City Olympics.

“What you got was right and what they got was wrong,” Gingrich said, summing up his view of Romney’s position.

But again and again, the Romney-Santorum animosity broke through the tumult on stage. While Romney was the first aggressor, Santorum also swung hard at the former Massachusetts governor for backing the 2008 bank bailouts and opposing federal intervention in the auto industry.